Abstract: To identify the optimal parameters for processing Guangdong Danxia 2 black tea, Headspace Solid-Phase Microextraction (SPME) combined with GC-MS (HS-SPME/GC-MS) and HPLC, etc. methods were used to analyze the effects of withering and fermentation duration on the aroma and quality of black teas. The results show that with the increase of withering time, the contents of alcohols increased significantly, which induced the release of flowery and fruit like aroma. The aldehydes decreased and the grass like aroma weakened. The contents of tea polyphenols and catechins decreased significantly after withering for 33 h. The water extracts increased and the total amino acids decreased. The results show that black tea had the best index and sensory qualities when withering for 33 h. With the increase of fermentation duration, the contents of alcohols showed the tendency of decreasing-no changes-decreasing significantly. The changes of esters were not obvious. The acids increased when fermentation duration increased. Amino acids decreased significantly after 12 h fermentation. The contents of tea polyphenols and water extracts also decreased, but showed significant difference after 12 h. The research concluded that the best fermentation duration was 12 h for Danxia 2 black tea, with the best quality and sensory test result. The black tea had sour taste when fermented for more than 12 h.

Key words: Danxia, processing, aroma, quality